A gene implicated in Carney complex, a rare disorder of the adrenal glands, appears to function as a molecular switch to limit cell growth and division, according to a study by researchers at the National Institutes of Health and other institutions. Mice lacking functional copies of the gene in the adrenal glands developed an overgrowth of adrenal tissue and were more susceptible to tumors in the gland.

The adrenal glands — one located on top of each kidney — produce hormones which help control heart rate, blood pressure, and other important body functions.

The researchers discovered that the normal process by which cells in the adrenal gland grow old and die is put on hold when the gene, known as Prkar1a, is deactivated. The Prkar1a gene is known to be involved in how the cell regulates its activities.

“Loss of Prkar1a appears to lead to unchecked cell growth in the adrenal glands,” said Dr. Constantine A. Stratakis, M.D., acting director of the Division of Intramural Research of the Eunice Kennedy Shriver National Institute of Child Health and Human Development and an author of the paper. “Our hope is that future studies of the gene and its functions will lead to a greater understanding of how certain types of cancer develop and ways to limit their growth.

The findings were published online in PLoS Genetics. The study’s first author is Isabelle Sahut-Barnola of Clermont University, France. Other authors include researchers at Ohio State University, Columbus and at three French institutions.

Carney complex is a rare disorder of the adrenal glands (http://ghr.nlm.nih.gov/condition/carney-complex). Individuals with Carney complex typically develop Cushing’s syndrome, a combination of weight gain, high blood pressure, diabetes, and other symptoms stemming from the overproduction of the hormone cortisol, which is produced by the adrenal glands. People with Carney complex are also predisposed to developing benign tumors of the heart and connective tissue, as well as benign and cancerous tumors of the adrenal and other glands. Previous studies have shown that people with Carney complex are likely to have a mutation in the Prkar1a gene.